#include <learnopengl/shader_s.h>
#include <GLFW/glfw3.h>
#include <stb_image.h>

#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
    glViewport(0, 0, width, height);
}

int main() {
    glfwInit();

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow *window = glfwCreateWindow(800, 600, "coordinate systems depth", NULL, NULL);

    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        return -1;
    }

    glEnable(GL_DEPTH_TEST);

    Shader ourShader("shader.vs", "shader.fs");

    float vertices[] = {
        -0.5f, -0.5f, -0.5f,                0.0f, 0.0f,
         0.5f, -0.5f, -0.5f,                1.0f, 0.0f,
         0.5f,  0.5f, -0.5f,                1.0f, 1.0f,
         0.5f,  0.5f, -0.5f,                1.0f, 1.0f,
        -0.5f,  0.5f, -0.5f,                0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,                0.0f, 0.0f,
        
        -0.5f, -0.5f,  0.5f,                0.0f, 0.0f,
         0.5f, -0.5f,  0.5f,                1.0f, 0.0f,
         0.5f,  0.5f,  0.5f,                1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,                1.0f, 1.0f,
        -0.5f,  0.5f,  0.5f,                0.0f, 1.0f,
        -0.5f, -0.5f,  0.5f,                0.0f, 0.0f,

        -0.5f,  0.5f,  0.5f,                1.0f, 0.0f,
        -0.5f,  0.5f, -0.5f,                1.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,                0.0f, 1.0f,
        -0.5f, -0.5f, -0.5f,                0.0f, 1.0f,
        -0.5f, -0.5f,  0.5f,                0.0f, 0.0f,
        -0.5f,  0.5f,  0.5f,                1.0f, 0.0f,

         0.5f,  0.5f,  0.5f,                1.0f, 0.0f,
         0.5f,  0.5f, -0.5f,                1.0f, 1.0f,
         0.5f, -0.5f, -0.5f,                0.0f, 1.0f,
         0.5f, -0.5f, -0.5f,                0.0f, 1.0f,
         0.5f, -0.5f,  0.5f,                0.0f, 0.0f,
         0.5f,  0.5f,  0.5f,                1.0f, 0.0f,

        -0.5f, -0.5f, -0.5f,                0.0f, 1.0f,
         0.5f, -0.5f, -0.5f,                1.0f, 1.0f,
         0.5f, -0.5f,  0.5f,                1.0f, 0.0f,
         0.5f, -0.5f,  0.5f,                1.0f, 0.0f,
        -0.5f, -0.5f,  0.5f,                0.0f, 0.0f,
        -0.5f, -0.5f, -0.5f,                0.0f, 1.0f,

        -0.5f,  0.5f, -0.5f,                0.0f, 1.0f,
         0.5f,  0.5f, -0.5f,                1.0f, 1.0f,
         0.5f,  0.5f,  0.5f,                1.0f, 0.0f,
         0.5f,  0.5f,  0.5f,                1.0f, 0.0f,
        -0.5f,  0.5f,  0.5f,                0.0f, 0.0f,
        -0.5f,  0.5f, -0.5f,                0.0f, 1.0f
    };

    unsigned int VBO, VAO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);

    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    // position attribute
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);
 
    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
    glEnableVertexAttribArray(1); 

    // load and create a texture
    unsigned int texture1, texture2;
    glGenTextures(1, &texture1);
    glBindTexture(GL_TEXTURE_2D, texture1);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    stbi_set_flip_vertically_on_load(true);
    int width, height, nrChannels;
    unsigned char* data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);
    if (data) {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
    }

    stbi_image_free(data);

    // texture 2
    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);

    // set the texture wrapping parameters
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    data = stbi_load("awesomeface.png", &width, &height, &nrChannels, 0);
    if (data) {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
    }

    stbi_image_free(data);

    ourShader.use();
    ourShader.SetInt("texture1", 0);
    ourShader.SetInt("texture2", 1);

    while (!glfwWindowShouldClose(window)) {
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);

        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);

        // activate shader
        ourShader.use();

        // create transformations
        glm::mat4 model = glm::mat4(1.0f);
        glm::mat4 view = glm::mat4(1.0f);
        glm::mat4 projection = glm::mat4(1.0f);

        model = glm::rotate(model, (float)glfwGetTime(), glm::vec3(0.5f, 1.0f, 0.0f));
        view = glm::translate(view, glm::vec3(0.0f, 0.0f, -3.0f));
        projection = glm::perspective(glm::radians(45.0f), 800.0f / 600.0f, 0.1f, 100.0f);

        unsigned int modelLoc = glGetUniformLocation(ourShader.GetProgramId(), "model");
        unsigned int viewLoc = glGetUniformLocation(ourShader.GetProgramId(), "view");
        
        glUniformMatrix4fv(modelLoc, 1, GL_FALSE, glm::value_ptr(model));
        glUniformMatrix4fv(viewLoc, 1, GL_FALSE, &view[0][0]);
        
        ourShader.SetMat4("projection", projection);

        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 36);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);

    // glfw: terminate, clearing all previously allocated GLFW resources.
    // ------------------------------------------------------------------
    glfwTerminate();
    return 0;
}

